Some of us are diagnosed with MTFHR mutation, which means that homocysteine levels might be elevated, which can impair the ability to process folate properly. If this is the case Folic Acid is prescribed in higher dosages

Checking your homocysteine levels is an easy blood test. I asked my doc to have my checked in preparation for ttc.

But I think researchers believe more is going on with folate than its affect on homocysteine. I've read articles suggesting that folic acid impacts early placental development and abnormal placental development may be a factor in preeclampsia. But I also read a review that said it doesn't affect development of preeclampsia at all. I'd talk to your doctor about what level is right for you. Just in case my doctor is not as informed as me (ha ha) I also come armed with research I want to discuss with him.